An Improved Enzyme-Linked Immunoassay for the Detection of Leptospira-Specific Antibodies

Am J Trop Med Hyg. 2018 Aug;99(2):266-274. doi: 10.4269/ajtmh.17-0057. Epub 2018 Jun 21.

Abstract

Leptospirosis is a neglected zoonotic disease with worldwide endemicity and continues to be a significant public health burden on resource-limited populations. Previously, we produced three highly purified recombinant antigens (rLipL32, rLipL41, and rLigA-Rep) and evaluated their performance of detecting Leptospira-specific antibodies in enzyme-linked immunosorbent assay (ELISA) as compared with the microscopic agglutination test (MAT). The overall sensitivity of this assay approached 90%. Recently, another recombinant antigen (rLigB-Rep) was prepared. We tested each individual antigen and a 1:1:1:1 mixture of these four antigens for the detection of Leptospira-specific antibodies in ELISA. The performance of these recombinant antigens was evaluated with a much larger febrile patient panel (337 MAT-confirmed positive sera and 92 MAT-negative sera from febrile patients). Combining the detection results of immunoglobulin M and immunoglobulin G from these four individual antigens, the overall sensitivity was close to 90% but the specificity was only 66%, based on the MAT reference method. The overall sensitivity and specificity of the four-antigen mixture were 82% and 86%, respectively. The mixture of four antigens also exhibited a broader reactivity with MAT-positive samples of 18 serovars from six major pathogenic Leptospira species. Given the limitations of MAT, the data were further analyzed by Bayesian latent class model, showing that ELISA using a 1:1:1:1 mixture still maintained high sensitivity (79%) and specificity (88%) as compared with the sensitivity (90%) and specificity (83%) of MAT. Therefore, ELISA using a mixture of these four antigens could be a very useful test for seroprevalence studies.

MeSH terms

  • Animals
  • Antibodies, Bacterial / immunology*
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / immunology
  • Bayes Theorem
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin M / blood
  • Leptospira / immunology*
  • Leptospirosis / diagnosis*
  • Leptospirosis / immunology
  • Recombinant Proteins / immunology
  • Sensitivity and Specificity
  • Serologic Tests / methods*
  • Zoonoses / diagnosis*
  • Zoonoses / immunology

Substances

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Immunoglobulin G
  • Immunoglobulin M
  • Recombinant Proteins